For cosmetic purposes it is known to use two-phase liquid products. for example hair setting lotion or products similar to setting lotion with a so-called top admixture. The top admixture consists of isoparaffins as the second phase. These are liquids which are highly volatile at room temperature and even more so at higher temperature, so that a sealed packing involves great difficulties. In addition isoparaffins have an extremely high leakage capacity. They have a low density and therefore always float on top in a two-phase mixture.
If these liquid products are bottled in conventional bottles, then considerable losses in top admixture arise as a result of diffusion and leakage in the region of the closure. For economic reasons, the closure caps of the bottles are provided with integrated sealing elements. in which case it is not possible to avoid capillaries and microscopic gaps between the neck of the bottle and the sealing element. The seals which on account of economic and functional requirements are mostly manufactured from polyolefins, only have a low diffusion density with respect to isoparaffins.